Signatures of planet ingestion among binary stars

Binary stars were born at the same time from the same material. Therefore, the two stars within a binary system should have identical chemical compositions. However, recent studies have found chemical differences between the stars in a given binary system. One tantalising explanation is that one of the stars has ingested a planet.

Our team at ANU were the first to discover a characteristic signature of planet formation. That signature lies in the chemical composition of the stars and was only revealed by our extremely accurate analysis. Other groups have confirmed our discovery and there are reports that planet engulfment events can be found in 15-35% of Sun-like stars.

Our discovery of stellar chemical signatures of planet formation remains controversial and other explanations (not involving planets) have been proposed. There is an urgent need for larger studies of binary stars to better understand which stars are most likely to host an Earth-like planet and to rule out other possible explanations for the chemical differences.

We are looking for keen students to join the project. They can be involved in different aspects, both observational (e.g., looking for radial velocity variations, spectroscopic confirmation and characterisation of the most interesting stars) and theoretical/computational (e.g., developing models to determine the mass of material ingested, exploring other phenomena which can mimic planet ingestion). 

For more information or other inquiries, please contact Dr David Yong ( or A/Prof Yuan-Sen Ting (